AMG 595 Engine

[Racer-X]

Does anyone have any details on that motor? The Racecar Engineering article was very short but it looks pretty neat.

I wonder if its going to be like the Mahle engine or what.

[JulianH]

Well it's a bit more than the Mahle :)

Some Infos can be found here, they are in German but also a lot of pictures:

http://de.scribd.com/doc/178160548/Joanneum-Racing-2cyl-Motordesign

Probably the guys from Karlsruhe or Graz can help even more.

[Racer-X]

Very cool. That torque curve is so flat!

[Z]

Very cool. That torque curve is so flat!
Racer-X,

I think that torque curve is "estimated". Quite easy to get it flat when you are just dreaming...
~~~o0o~~~

I recall commenting on this engine some time ago, but to repeat, WHAT A WASTED OPPORTUNITY!

There is a "Decision Matrix" table about 1/3 way down Julian's linked document that compares this L2 engine with 120 & 60 degree V2s, an F2, and an L1 (= single). Quite clearly, the L2 was chosen long before this matrix was drawn up, and no amount of real-life facts were going to get in the way! Namely, the single was a close second on points, but only because it got 0/25 (!!!) for "Leistung" (= "performance", or "power"?), while the L2 managed 25/25! So singles make no power at all???!!!

Also interesting is that with their projected 75 kW, the "Tractive Force" curve (about 3/4 way down) indicates that only two gears are really needed. Any lower than their second gear gives more than 3 kN (= ~300 kg) force, which is more than enough to spin the rear wheels of most any FSAE car. Their fourth gear tops out at ~130 kph, which is higher than needed, except perhaps as an overdrive for lower fuel use. A "low" gear perhaps slightly above their 2nd, and a "high" slightly under their 4th, would be enough. It would make for easier driving/gear changing (just pull or push on gear lever, with neutral between), and less chance of spinning when exiting corners.

Look at the engine pictures at the bottom of the document. Now imagine a single-crank in the same place, with its single cylinder-head pushed back and down to take the place of the unnecessary gears, and the diff still in roughly the same place. Now the engine-drivetrain package has a lower CG and is a bit lighter. And as noted on another recent thread, turboed-singles can easily make similar power to this L2.

Furthemore, the driver can now also be pushed backwards about a foot (= ~0.3m), probably enough to get their feet behind the front axle line of a ~minimum wheelbase car. This further reduces overall mass of the car (because shorter chassis), and more importantly reduces Yaw inertia for better agility. It also puts greater percentage of weight on the rear axle, so the car (say now at total mass = 200kg) can use all of that 3kN thrust force for 1.5G acceleration without wheelspin.

So the possibility of a simpler, cheaper, lighter, and much faster car, is all ruined because of someone's preconcieved notion of what is the "best engine". :(

Z

[Racer-X]

Racer-X,

I think that torque curve is "estimated". Quite easy to get it flat when you are just dreaming...
~~~o0o~~~

I recall commenting on this engine some time ago, but to repeat, WHAT A WASTED OPPORTUNITY!

There is a "Decision Matrix" table about 1/3 way down Julian's linked document that compares this L2 engine with 120 & 60 degree V2s, an F2, and an L1 (= single). Quite clearly, the L2 was chosen long before this matrix was drawn up, and no amount of real-life facts were going to get in the way! Namely, the single was a close second on points, but only because it got 0/25 (!!!) for "Leistung" (= "performance", or "power"?), while the L2 managed 25/25! So singles make no power at all???!!!

Also interesting is that with their projected 75 kW, the "Tractive Force" curve (about 3/4 way down) indicates that only two gears are really needed. Any lower than their second gear gives more than 3 kN (= ~300 kg) force, which is more than enough to spin the rear wheels of most any FSAE car. Their fourth gear tops out at ~130 kph, which is higher than needed, except perhaps as an overdrive for lower fuel use. A "low" gear perhaps slightly above their 2nd, and a "high" slightly under their 4th, would be enough. It would make for easier driving/gear changing (just pull or push on gear lever, with neutral between), and less chance of spinning when exiting corners.

Look at the engine pictures at the bottom of the document. Now imagine a single-crank in the same place, with its single cylinder-head pushed back and down to take the place of the unnecessary gears, and the diff still in roughly the same place. Now the engine-drivetrain package has a lower CG and is a bit lighter. And as noted on another recent thread, turboed-singles can easily make similar power to this L2.

Furthemore, the driver can now also be pushed backwards about a foot (= ~0.3m), probably enough to get their feet behind the front axle line of a ~minimum wheelbase car. This further reduces overall mass of the car (because shorter chassis), and more importantly reduces Yaw inertia for better agility. It also puts greater percentage of weight on the rear axle, so the car (say now at total mass = 200kg) can use all of that 3kN thrust force for 1.5G acceleration without wheelspin.

So the possibility of a simpler, cheaper, lighter, and much faster car, is all ruined because of someone's preconcieved notion of what is the "best engine". :(

Z

I was thinking it was from an inertia dyno, but then I don't read German.

I feel there are a lot of odd choices on that motor as a whole. They put a lot of work into designing an engine but stuck to such a conventional path. Which I think is very limiting. Like you were saying they could have just used a two speed (maybe a planetary gear set on the diff). Rather than bothering with a bulky turbo+intercooler set up they could have made it a high revving twin that just reaches choked flow N/A. Its definitely and example of some people over engineering something to an absurd point.

Like the WWU V8 it might be a poor choice in my opinion but it sure is a cool engine.

[murpia]

Why did they not put any suspension mounts on those gorgeous castings???...

Regards, Ian

[JWard]

Ian, if you have a look at some car launch pictures of the two teams using this engine, you'll see they've gone for engine cradles. I imagine no one wanted to compromise on their choice of suspension pickup points. Which would be an issue with two different teams using the engine. However I imagine the aforementioned engine cradle allows transmittal of some suspension forces into the engine casing so that the cradle and engine together are a little load bearing / stiffen the rear up.

Interestingly the carbon tube cradle I've seen somewhere didn't look like it was used on the end vehicle. (Nasty heat coming off that exhaust, turbo and inter cooler possibly compromised the integrity of the overall structure possibly? whether that be the carbon tubes themselves or the bonding of the inserts.

still, as a technical excercise, all very impressive. Does anyone know anything about whether any of elements of the design were taken from off the shelf designs / components? i.e. any of the valvetrain, conrod, piston?

[RenM]

Racer-X,
WHAT A WASTED OPPORTUNITY!


wow, one of the few times that i have to say i think Z is right (even though i would have build a different engine then him).

The Mahle Engine was a good concept badly executed.
The AMG Engine to me is a bad concept well executed.

[Mbirt]

There is a "Decision Matrix" table about 1/3 way down Julian's linked document that compares this L2 engine with 120 & 60 degree V2s, an F2, and an L1 (= single). Quite clearly, the L2 was chosen long before this matrix was drawn up, and no amount of real-life facts were going to get in the way! Namely, the single was a close second on points, but only because it got 0/25 (!!!) for "Leistung" (= "performance", or "power"?), while the L2 managed 25/25! So singles make no power at all???!!!The naturally aspirated power curve for the Rotax DS450 single showing that it only produces 32 kW peak is laughable. Half the effort put into a restricted naturally aspirated setup as was invested in the turbocharged single cylinder concept would have yielded at least 44 kW. And the use of a lapsim to assign "Leistung" points in the decision matrix would show a ~44 kW L1 scoring 20-25 points, while 32 kW definitely deserves more than 0 points because major FS/FSAE competitions have been won by a team with an engine producing about the same power.

[Z]

The naturally aspirated power curve for the Rotax DS450 single showing that it only produces 32 kW peak is laughable.
...
... the use of a lapsim to assign "Leistung" points in the decision matrix would show a ~44 kW L1 scoring 20-25 points, while 32 kW definitely deserves more than 0 points because major FS/FSAE competitions have been won by a team with an engine producing about the same power.
I can picture the Decision-Matrix Design Review Committee Meeting;

Designer1, "Dammit! The single is still the winner... And we can't reduce its points any more for simplicity, or cost, or even weight, because it's clearly well ahead of the others there. Hmmm, what if we only give it HALF points for power, because it's only got half as many cylinders?"

Designer2, "Err..., nope. It still wins!"

Designer1 "Aaarghh!!!... Well, we'll have to give it 0/25 for power! Hopefully no one will notice...""

The really sad thing is that you students can look forward to a lifetime of the above decision making processes... :)
~~~o0o~~~

Further to my earlier comments, the dissapointing thing about the whole project is the obviously very large cost/effort that has gone into it, for very little benefit. In essence, a huge effort to design and build a fairly standard FSAE powertrain. Specifically;

1. The overall package shape is very similiar to most FSAE engine-to-diffs, so no gain in overall car packaging (ie. it enforces the same excessively large car Yaw MoI). Likewise, little or no lowering of overall weight or CG.

2. The gear final-drive to the diff tidies up that area a bit, but that can be, and has been, done many times before with off-the-shelf bike engines.

3. The "reversed" cylinder head moves the hotter exhausts away from the seat-back, but that "problem" can be solved with some heat shielding, so no big gain there.

4. The "reverse rotation" crank gives beneficial anti-roll gyro forces in a corner, but this somewhat cancelled out by fitting the highish MoI clutch-basket to a "forward rotating" shaft. So, in total, a significant benefit missed there.

5. The direct-fuel-injection may give a tiny improvement in power/driveability/fuel-efficiency, but same could be had by fitting a bespoke DI-cylinder-head to any motocross/ATV/whatever engine. This really just an academic exercise, ie., good for learning, but giving little winning advantage in FSAE. BTW, given the injectors seem to be vertical, where are the spark-plugs?

6. Why is there a 7-stage (!) oil-pump? And why, given this is a from-scratch design, drive it by an extra chain at crank speed? Ie., why not drive (fewer) pumps direct off the ends of existing shafts (= more reliable, lighter, cheaper...)?

In summary, I see a lot of money spent polishing the little details of a meant-for-a-bike engine, with next to no consideration given to the "big-picture" FSAE issues. To repeat, these issues include overall package shape (giving low overall car weight and CG), high reliability (= simplicity), low cost (= simplicity), and so on.

Z

(PS. Does anyone know what turbo they use? It has an odd looking turbo-inlet/wastegate??)

[AxelRipper]

As much as I like the engine, I still find myself questioning it's legality per:

IC1.7.1 Turbochargers or superchargers are allowed if the competition team designs the application. Engines that have been designed for and originally come equipped with a turbocharger are not allowed to compete with the turbo installed.

Now, I understand that at the time of its design UAS Graz had plenty of experience with forced induction, but since it is branded AMG, and most of the literature touts it as being an AMG developed engine with the help of the Unis, and every iteration of this engine is turbocharged (and its design from the beginning was clearly with intent to be turbocharged).......

[Kevin Hayward]

Axel,

I agree that the engine should be considered illegal as per the rule stated. The engine was very clearly turbo charged by its original equipment. The only wriggle room is the team designed application point. It would be great to see some clarification on that point.

I think there is generally a little lattitude given to teams when they undertake something like a custom engine on these sorts of points. The rules aren't written on the basis that a large number of teams will be making their own power units. Whether this is a correct attitude given that similar attempted advances in suspension, aero and chassis systems appear to undergo much more public scrutiny, is up to you to decide.

Z,

Once again some good points. I will say that I think the exhaust pointing rearwards is a bit more of an advantage that it appears at first. The heat can be readily dealt with using heat shields and insulation, and althoguh these are usually much heavier than you would expect, it is not much of an issue.

The bigger gain is that the exhaust generally needs to have a lot of air flow around it and that means space. If you put this engine in a typical FSAE car then the gain would be almost nothing, however moving the exhaust rearwards can end up bringing the driver much closer to the engine, and simplify the chassis by requiring no side exit of exhaust tube(s). To make best use of this is would require a bit of lateral thinking in the rear end of the car. I am still to see a rear end of a FSAE vehicle that is truly elegant and simple design. The packaging of a motorcycle engine based powertrain, including forward facing exhaust, and double a-arm setups make for a real mess at the back end of these cars. Some teams hide it better with the monocoque engine covers.

I think we are yet to see a FSAE car with a custom engine that makes best use of the engine to better design the rest of the car. I do think it is coming, and that we will start to see the early attempts pretty soon.

Kev

[JulianH]

Kevin / Axel,
at every competition, that the engine participated in, there were discussions about the legality. So far every rules committee declared the engine as legal. The system is acknowledged as student-built.

[Pat Clarke]

Of course, the legality of the turbocharger system will really come under scrutiny next year when the students presenting the engine will not be the designers of the system, but are instead using an "Engine that has been designed for and originally came equipped with a turbocharger is not allowed to compete with the turbo installed".

Unless, of course, they design and build a completely new turbo system or run it in unblown form.

Pat